Found an interesting source book today that provides alittle info on Averland ...
The book was called "WFRP Companion" put out by Black Industries in 2006, who has been printing some of GW's stuff it seems. There is a lengthy section inside regarding the river ways of the Empire, including a map with some towns listed on it. In Averland, the towns listed on the Aver River are Streissen and Averheim, with Pfungzig being listed on the Blue Reach and then further down Schramlen, Sigmarigen (these two are listed on the "home16" site, but not the "madalfred" site), and Bernloch (listed on both sites) as the river gets closer to the World's Edge Mountains. On the Upper Reik, Wuppertal and Lonigbruck are followed by Steingart (also not listed on either of the previously mentioned sites), Agbeiten, and Hochsleben, along with Grenzstadt guarding Black Fire Pass. Interestingly, the same map has the Moot covering the rest of the territory between the Aver Reach and Blue Reach rivers.
Haven't seen a copy of "Sigmar's Heirs" yet, although Black Industries does have several other publications that might provide helpful info on other Empire provinces, cities, towns and villages, too.